[Results of electromyographic studies with central muscle relaxants--feasibility of objectivization and standardization].

The following drugs, mostly postulated acting at a supraspinal or spinal level as diazepam, chlormezanone and orphenadrine citrate were proved for their effectiveness in lessening tension of muscles. This was assessed by electromyography recording different neurophysiological phenomenons as mono- and polysynaptic reflex responses (H-reflex and unloading reflex as a result of a suddenly muscle relaxation (= post-reflex inhibition phase/silent period) and tiredness reaction. This investigations were performed on at least 65 patients. The outcomes are: statistical significant increase of the silent period of the unloading reflex under the treatment with diazepam and orphenadrine citrate. Diazepam also extended the time between the initial electric stimulus and H-reflex phenomenon. Evaluating these results it might be obvious that diazepam is acting on supraspinal level and the spinal too, orphenadrine citrate only on the supraspinal one. Chlormezanone showed no effect according to that protocol on all mentioned neurophysiological parameters.